.. include:: sub.txt ===================== BbarBrick u-p Element ===================== bbarBrickUP is a 8-node mixed volume/pressure element, which uses a tri-linear isoparametric formulation. Each node has 4 degrees-of-freedom (DOF): DOFs 1 to 3 for solid displacement (u) and DOF 4 for fluid pressure (p). This element is implemented for simulating dynamic response of solid-fluid fully coupled material, based on Biot's theory of porous medium. .. function:: element('bbarBrickUP', eleTag,*eleNodes,matTag, bulk, fmass, permX, permY, permZ,) :noindex: ========================================== =========================================================================== ``eleTag`` |int| unique element object tag ``eleNodes`` |listi| a list of eight element nodes ``matTag`` |int| Tag of an NDMaterial object (previously defined) of which the element is composed ``bulk`` |float| Combined undrained bulk modulus Bc relating changes in pore pressure and volumetric strain, may be approximated by: :math:`B_c \approx B_f/n` where :math:`B_f` is the bulk modulus of fluid phase (:math:`2.2\times 10^6` kPa (or :math:`3.191\times 10^5` psi) for water), and n the initial porosity. ``fmass`` |float| Fluid mass density ``permX``, ``permY``, ``permZ`` |float| Permeability coefficients in x, y, and z directions respectively. ``bX``, ``bY``, ``bZ`` |float| Optional gravity acceleration components in x, y, and z directions directions respectively (defaults are 0.0) ========================================== =========================================================================== .. seealso:: `Notes `_